E2.1 Ignition retries exceeded - flame never proven (1 hour lockout)

What the control is telling you

The furnace tried to light but never saw flame, used up its ignition attempts and went into a 1-hour lockout. S8B1/S8X1/S8X2 list lockout after 3 tries; the S8V2 code table says 7 tries, its flowchart says 6, and its wiring diagram label says 2 retries - check the label on the unit.

Applies to: Trane S8V2 (80%, 2-stage, variable speed, Link) and S8B1 / S8X1 / S8X2 (80%, 1- and 2-stage)

Likely causes

• Gas supply off, valve switch OFF, or inlet pressure too low or above 13.8 in. W.C.
• No 24 VAC to gas valve or debris in the valve
• Igniter weak or out of position
• Burners dirty or misaligned, low manifold pressure
• Dirty flame sensor, poor ground or loose sensor wire

Test and repair steps

1. Cycle power to reset the lockout, then watch one full ignition attempt.
2. With all other gas appliances running, check inlet pressure: max 13.8 in. W.C., not below the rating-plate minimum (5.0 in. W.C. NG, 11.0 in. W.C. LP).
3. If there is no gas pressure at the manifold during trial, check the valve on/off switch, 24 VAC to the valve and for debris in the valve.
4. On a 1st stage call, manifold should read about 1.7 in. W.C. on natural gas or about 6.0 in. W.C. on LP; adjust if off.
5. If gas lights but not all burners catch within 4 seconds, clean and align burners and check igniter position.
6. Measure flame signal with a meter on DC volts across the two FP pads (1 VDC = 1 microamp). Normal is 0.75 to 3.0; under 0.5 points to a dirty sensor, bad ground, sensor position or wiring.

Settings for these units

Clearance to combustibles · Trane S8V2

24 in. front service access.

3 in. in front of the combustion air openings.

Return filter size by cabinet width · Trane S8V2

Filters are field supplied and mounted outside the cabinet.

Over 1600 CFM upflow: return on both sides, one side plus bottom, or bottom only.

• Return filter size by cabinet width · Trane S8B1, Trane S8X1, Trane S8X2

Models that show this code

37 models in Trane S8V2, Trane S8B1, Trane S8X1, Trane S8X2

Other codes on the same units

• E01 Furnace control internal failure
• E2.2 Flame recycles exceeded - flame lost after lighting (1 hour lockout)
• E2.3 1st stage gas valve not powered when it should be (10 times)
• E3.1 1st stage pressure switch (PS1) closed when it should be open
• E3.2 1st stage pressure switch (PS1) open when it should be closed
• E3.3 2nd stage pressure switch (PS2) closed when it should be open
• E3.4 2nd stage pressure switch (PS2) open when it should be closed
• E04 Open limit (main limit, rollout or reverse airflow)